Currently, radar sensors or radar detectors with a simple radiation characteristic are used. That means that a radar antenna transmits preferably in a main radiation direction and receives from this direction. The monitoring range for a number of radar applications is broader, however, than what one radar antenna alone can cover. Consequently, generally two or more than two independent radar antennas are used, which each cover a separate angular range by having their main radiation directions arranged at an angle to each other. This way, the two radiation characteristics of the radar antennas overlap to form a broader overall characteristic. In aggregation, the entire monitoring range is detected by the different radar antennas.
To provide an antenna device that is as compact as possible, the goal is to arrange the radar antennas required to cover a specified monitoring range or detection range on a single printed circuit board (PCB—Printed Circuit Board). When several radar antennas are arranged on a single circuit board, however, this board becomes too large. This prevents a more compact arrangement of a radar detector.
Conversely, if the range is specified, a circuit board is desired on which as many radar antennas as possible can be used in the same main radiation direction to improve or increase the spatial resolution of the radar detector.